Bring a large pot of salted water to a boil over medium-high heat. Cook the pasta until just al dente, drain and set aside.
Heat the olive oil in a medium cast iron skillet over medium heat. Add the onion and green chilies, stirring occasionally, until the onions become soft and translucent, about 5 minutes.
Add the butter and allow to melt, then whisk in the flour, continuing to stir until pale brown, about 2 minutes. Whisk in the milk and bring to a simmer. Continue to simmer until thick, about 10 minutes.
Whisk in the Velveeta® cheese, a few cubes at a time, until it is all incorporated. Whisk in the cheddar cheese and the Monterey jack cheese until the mixture becomes smooth.
Add the cooked pasta to the cheese mixture, and stir until the mixture is thoroughly combined. Add to a large cast iron skillet.
Heat the broiler to high. Sprinkle the top of the macaroni and cheese mixture with panko breadcrumbs and broil until the top is golden brown, about 3 to 5 minutes. Check occasionally to make sure that it does not burn.
Garnish the mac and cheese with cilantro and green onions then serve.